The impact of bariatric surgery on renal and cardiac functions in morbidly obese patients

Nephrology Dialysis Transplantation, Dec 2012

Background Cardiac adaptation to obesity includes both structural and functional alterations in the heart. The kidneys also suffer the consequence of excessive increase of body weight. This study aims to assess the functional, cardiac and renal changes in a cohort of morbidly obese patients, as well as changes after bariatric surgery–the last therapeutic option for these patients.

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The impact of bariatric surgery on renal and cardiac functions in morbidly obese patients

Mara Luaces 1 2 Ernesto Martnez-Martnez 0 Manuel Medina 4 Mara Miana 0 Noem Gonzlez 3 Cristina Fernndez-Prez 1 Victoria Cachofeiro 0 0 Departamento de Fisiologa , Facultad de Medicina, Universidad Complutense and Instituto de Investigacin Sanitaria del Hospital Gregorio Maran , Madrid, Spain 1 Instituto de Investigacin Sanitaria del Hospital Clnico San Carlos (IdISSC) , Madrid, Spain 2 Servicio de cardiologa. Instituto cardiovascular. Hospital Clnico San Carlos. Madrid, Spain 3 Servicio de Endocrinologa-Medicina Interna, Hospital Universitario de Fuenlabrada , Fuenlabrada, Madrid, Spain 4 Servicio de Ciruga General y del Aparato Digestivo, Hospital Universitario de Fuenlabrada , Fuenlabrada, Madrid, Spain Background. Cardiac adaptation to obesity includes both structural and functional alterations in the heart. The kidneys also suffer the consequence of excessive increase of body weight. This study aims to assess the functional, cardiac and renal changes in a cohort of morbidly obese patients, as well as changes after bariatric surgery-the last therapeutic option for these patients. Methods. Patients referred for bariatric surgery were prospectively included. In each case, transthoracic echocardiography and a blood test were performed before the procedure and repeated 1 year after surgery. The estimation of the glomerular filtration rate (GFR) was addressed by the Cockroft-Gault lean body weight formula. Results. Sixty-one patients completed the 1-year followup. Of these, 81.9% were female. The mean age was 41.1 9.8 years and the mean body mass index was 47.4 5 kg/m2, decreasing to 30.5 5.07 kg/m2 after the procedure. Before surgery, the estimated GFR was 92.7 25.4 mL/min, with hyperfiltration being present in 14.8% of patients, whereas an impaired GFR was detected in 8.3%. Patients showed preserved systolic function and cardiac remodelling. Diastolic function was abnormal in 27.9% of patients. At the 1-year follow-up, favourable changes in the left ventricular geometry and related haemodynamic status were observed. There was no significant change in the estimated GFR in the overall group, although hyperfiltration was ameliorated in 9.8% and a poor GFR was improved in 3.3.%. The improvement was not associated with changes in either blood pressure or the BMI. However, in this group of patients the amelioration of the GFR was associated with an increased stroke volume and improvement in diastolic function. Conclusions. In morbidly obese patients, GFR is usually normal and only a small percentage of them show hyperfiltration or a reduced GFR. Bariatric surgery has a favourable impact on renal function in only a reduced group of patients who also experience an improvement in cardiac performance. Introduction Changes in lifestyle that have occurred throughout the last decades have been used to explain the current sharp rise in the prevalence of obesity, a major health problem associated with increased morbidity and mortality, especially those of a cardiovascular origin [1]. Obesity also promotes the development of other co-morbidities such as diabetes, hypertension and dyslipidaemia, which are important risk factors for chronic kidney disease progression and death [24]. The heart adapts to obesity through remodelling, which is a process that can involve left ventricular hypertrophy and dilation, as well as atrial changes [57]. These changes can affect cardiac function and finally initiate the development of heart failure. At the renal level, obesity is accompanied by hyperfiltration, renal hypertrophy and other changes that can promote the development of proteinuria in the long term [3, 4, 8, 9]. Body weight loss is a fundamental strategy for improving the risk of obese patients, and especially so for those with morbid obesity for which weight reduction is difficult to attain through conventional means. Bariatric surgery is a useful way of losing weight for these patients since the reduction can reach between 50 and 60% of body weight [10]. Some studies have demonstrated that bariatric surgery improves cardiac remodelling [5, 11] and is associated with a reduced number of cardiovascular deaths and lower incidence of cardiovascular events in obese adults after 15 years of follow-up [12]. Regarding the renal consequences, it is not well established whether these beneficial effects are maintained in the long term even though a reduction in proteinuria has been reported [13, 14] (or whether these changes are associated with or accompanied by the improvement of other alterations observed in obese patients). Therefore, the aim of this study was to evaluate the impact of bariatric surgery on renal function and other targets of organ damage in morbidly obese patients at 1 year after bariatric surgery. Materials and methods This clinical study included all patients referred for bariatric surgery. A panel including surgeons, endocrinologists and cardiologists carried out the selection of candidates. Inclusion cr (...truncated)


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María Luaces, Ernesto Martínez-Martínez, Manuel Medina, María Miana, Noemí González, Cristina Fernández-Pérez, Victoria Cachofeiro. The impact of bariatric surgery on renal and cardiac functions in morbidly obese patients, Nephrology Dialysis Transplantation, 2012, pp. iv53-iv57, 27/suppl 4, DOI: 10.1093/ndt/gfs529